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A safer way for Makers and DIY'ers to control mains ac power with a microcontroller.

PowerSwitch Tail II
PowerSwitch Tail II Kit
240vac Kits
16-ch PWM Controller
PowerSSR Tail
ZeroCross Tail
PowerState Tail
CB500 Circuit Breaker
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ZeroCross Tail
(PN 80175)
$17.99 each 

In Stock!


A power cord that creates zero voltage crossing sync pulses for phase control (light dimming) applications.


  • Use with the Arduino or other microcontroller and our PowerSSR Tail to phase control ac power. (The ZeroCross Tail provides the sync pulse signal only and by itself will not deliver phase controlled power.)
  • Applications include light dimmers (Arduino sample sketch or variable dimmer) and motor speed controls.
  • Open collector output for interface to any microcontroller. A pull up resistor (10K ohm) to an external power source is required for logic level signal output.
  • Works with Arduino, Raspberry Pi, Beaglebone, and other 3.3 or 5 volt MCUs.
  • Output isolation from ac side greater than 5000vrms.
  • Power is extended to receptacle side power cord providing a convenience outlet (up to 12 amps).
  • Built-in LED indicates active output.
  • No exposed 120vac voltages and no dangerous 120vac wiring required. Can be installed by non-technical users: Instruction sheet.
  • Plugs into standard 120vac 3-prong household outlets, power strips, and extension cords.



  • AC input: NEMA 5-15P Plug, standard 120vac with ground.
  • AC output: NEMA 5-15R Receptacle, standard 120vac with ground.
  • Output: Photo transistor with collector and emitter leads accessible. External pull-up resistor required for logic level signal.
  • Output voltage: Pull-up resistor to 48vdc maximum.
  • Output current: 50ma sink maximum.
  • Output polarity: Positive going pulse at zero crossing.
  • Output to ac circuit isolation: >5,000vrms.
  • AC pass-thru capacity: 12amps max @ 120vac.
  • Indicator: LED indicates when output is active.
  • Mounting: Two #6 screws or free standing.
  • Indoor use only.


Our liability is limited to the purchase price of this product only. By using this product you agree that, LLC can not be held liable for any damages or injuries resulting from use, misuse, or repair. This product is for indoor use only.